1. Field of the Invention
This invention relates to a visual display of a panoramic region and, in particular, to such a visual display in which visual context is provided for an active display displayed in a mobile display window.
2. Related Art
It can be desirable to provide a display of the content of a spatial region that is larger than a field of view of a visual data acquisition device (e.g., video camera, video-enabled motion picture camera, still photo camera) that is to be used to obtain visual data representing an image within the spatial region. Herein, for convenience, such a display is sometimes referred to as a “panoramic display” and such a spatial region is sometimes referred to as a “panoramic region.” Additionally, the visual data representing a single image obtained by a visual data acquisition device is referred to herein as a “frame” of visual data.
To produce a display that includes content covering a panoramic region, multiple frames of visual data must be obtained such that at least two of the frames of visual data correspond to spatial regions that are not coincident. Different types of displays can be produced, depending on characteristics of the frames of visual data, or the way in which the frames of visual data are used to generate a display.
For example, in one type of panoramic display (sometimes referred to herein as a “mobile active display”), a set of temporally sequential frames of visual data is used to generate the display. Each frame of visual data is used in sequence to produce a corresponding displayed image on a display screen. (Herein, “display screen” refers generally to any medium on which a visual display is presented.) Only one displayed image appears on the display screen at a time. (As used herein, a currently displayed image that is part of a sequence of images generated from temporally sequential frames of visual data is an “active image,” the area of a display screen in which the active image is displayed is an “active window,” and a display of a series of active images is an “active display.”) Each displayed image is positioned on the display screen with respect to the position of other displayed images on the display screen in accordance with the spatial relationship in the panoramic region of the content of the displayed image to the content of the other displayed images. Thus, an active display is produced in which the active image is displayed in a display window that moves about the display screen in accordance with the content of the active image.
In another type of panoramic display (sometimes referred to herein as a “mobile static display”), a set of frames of visual data that represent images at the same point in time is used to generate a display. (Alternatively, a similar display can be generated from a set of frames of visual data obtained at different points in time if the content of the images represented by the frames remains essentially constant.) A series of images or sets of images corresponding to a sequence of adjacent frames or sets of frames (i.e., frames or sets of frames representing images that are most spatially proximate to each other in a particular direction), respectively, are successively displayed in a display window. The display window may or may not remain fixed on a display screen. If so, the fixed display window appears to open onto a scene that is passing by the display window. If not, the location of the display window on the display screen changes in accordance with the content of the image(s) in the display window so that the moving display window appears to open onto a fixed “hidden” scene. Thus, a display is produced in which different parts of a static panoramic image can be successively displayed in a display window.
In both of the above-described displays, as the display window shows different parts of a panoramic region, previously displayed content that can no longer be displayed in the display window is removed from the display screen. Consequently, context for the images displayed in the display window that might otherwise be provided by the removed content is lost (except insofar as a perception of the removed content is retained in the mind of a viewer). Since it can be desirable to provide such context, the above-described panoramic displays may not provide a viewing experience that is as enjoyable, rich and/or informational as desired. Additionally, the mobile static display does not provide the dynamism associated with the display of an active image, which, again, may limit the enjoyability, richness and/or informativeness of the viewing experience.
In still another type of panoramic display, an active display of a part of a panoramic region is positioned within a larger static display of the panoramic region. However, the frames of visual data used to produce the active display are different from the frames of visual data used to produce the static display, so that the two displays appear disjointed and otherwise unrelated to each other to an undesirable degree.
In yet another type of display (sometimes used in flight simulators), a small, relatively high resolution active display is positioned within a larger, relatively low resolution active display. However, the active displays are generated from sets of frames of visual data that must be acquired simultaneously by separate visual data acquisition devices, making the acquisition of visual data for such a display relatively expensive and complex. Further, the simultaneous display of both active displays requires expensive and/or complex display apparatus and methods to, for example, synchronously and seamlessly display both active displays.